Yes you can use an app called "launch at boot" to launch any app you like from boot or sleep

If you need specific Android apps or are a nvidia gamer, you'll want to stick with the shield.

If it's going to be used for mostly iptv, there are better (this is always subjective of course) options and significantly most cost efficient options.

You could probably have 2 dedicated boxes for the price of the shield and both will probably yield a much better viewing experience. Some boxes look very similar to satellite receivers and can be found cheap.

I'd recommend checking out my video reviews on receivers over at /r/iptvgta it's the top sticky.

I have put my shield review on there though because there is so much info out there on that already.

I'd try to avoid emulators as much as possible but some people have got shield working well with iptv. But a simple search will yield many issues people have encountered.

I have several IPTV services that work great as a standalone apps on the Shield. In addition, you can have it setup to boot directly into the IPTV service or just keep it in sleep mode. Most people seem to think you need to run STB but that's not necessary for a lot of IPTV services that have apk's available

I have one and its a great KODI and Plex box... but there are plenty of cheaper Android TV boxes out there. Some that even do HDR10.

I kind of wish I'd gone that route because I almost never use it for gaming. And if it did Dolby Vision the price might be justifiable, but it doesn't.

Edit: if you can get one for $100 or less, go for it.